The processes of weathering affects rocks exposed at the coast. Freeze-thaw weathering in particularly effective if the rock is porous (contains holes) and permeable (allows water to pass through it). This can lead to dramatic rockfalls as shown below.
Full explanation as to how freeze-thaw weathering works can be found at the following link:
Mass movement
Mass movement is the downhill movement of material inder the influence of gravity. In 1993 60m of cliff slid onto the beach near Scarborough in North Yorkshire, taking with it part of Holbeck Hall Hotel.
Marine Processes Coastal ersoion
Erosion – use the acronym CASH Corrasion – (abrasion) is caused by large waves hurling beach material against the cliff Attrition – is when waves cause rocks and boulders on the beach to bump into each other and to break up into small particles Solution – (corrosion) is when salts and other acids in seawater slowly dissolve a cliff Hydraulic pressure (power/action) – is the force of waves compressing air in cracks in a cliff
One final process of erosion is:
Abrasion: this is the 'sandpapering' effect of pebbles grinding over a rocky platform, often causing it to become smooth.
Coastal transportation
Processes of Transportation
Traction – rolling stones along the sea floor (needs the most energy)
Saltation – sand-sized particles bounce along the sea floor in a ‘leap frog’ movement
Suspension – silt and clay-sized particles are carried within the water flow·
Solution – some minerals dissolve in the water (this needs the least energy)
Waves approach the beach in the same direction as the wind
When the wave breaks, swash carries material up the beach at the same angle as the wind
The backwash carries the material straight back down the beach under gravity·
This process slowly moves material along the coastline
Remember when drawing:
To draw in a beach
An arrow showing the prevailing wind
An arrow showing the direction of longshore drift
To draw in the movement of the pebbles
To use the terms ‘swash’, ‘backwash’ and ‘gravity’ when describing the movement of the pebbles
Coastal deposition
Deposition occurs in areas where the flow of water slows down. The sediment can no longer be carried or rolled along an has to be deposited. Coastal depostion most commonly occurs in bays, wherew the energy if the waves is reduced on entering the bay. This explains the presence of beaches in bays and accounts for the lack of beaches at headlands, where the energy of the waves is uch greater.
Coastal proceses can be split into two different categories:
Video showing the processes of erosion - http://www.bbc.co.uk/learningzone/clips/weathering-erosion-and-coastal-features/4022.html
Excellent animation showing coastal processes and defences - http://www.as.uky.edu/academics/departments_programs/EarthEnvironmentalSciences/EarthEnvironmentalSciences/Educational%20Materials/Documents/elearning/module14swf.swf
Weathering
The processes of weathering affects rocks exposed at the coast. Freeze-thaw weathering in particularly effective if the rock is porous (contains holes) and permeable (allows water to pass through it). This can lead to dramatic rockfalls as shown below.
Full explanation as to how freeze-thaw weathering works can be found at the following link:
http://onlinegeography.wikispaces.com/Ice+as+a+shaping+agent
Mass movement
Mass movement is the downhill movement of material inder the influence of gravity. In 1993 60m of cliff slid onto the beach near Scarborough in North Yorkshire, taking with it part of Holbeck Hall Hotel.
Marine Processes
Coastal ersoion
Erosion – use the acronym CASH
Corrasion – (abrasion) is caused by large waves hurling beach material against the cliff
Attrition – is when waves cause rocks and boulders on the beach to bump into each other and to break up into small particles
Solution – (corrosion) is when salts and other acids in seawater slowly dissolve a cliff
Hydraulic pressure (power/action) – is the force of waves compressing air in cracks in a cliff
One final process of erosion is:
Abrasion: this is the 'sandpapering' effect of pebbles grinding over a rocky platform, often causing it to become smooth.
Coastal transportation
Processes of Transportation
Longshore Drift
Video showing how Longshore Drift works - http://www.bbc.co.uk/learningzone/clips/landforms-created-by-longshore-drift-and-coastal-deposition/9965.html
Remember when drawing:
Coastal deposition
Deposition occurs in areas where the flow of water slows down. The sediment can no longer be carried or rolled along an has to be deposited. Coastal depostion most commonly occurs in bays, wherew the energy if the waves is reduced on entering the bay. This explains the presence of beaches in bays and accounts for the lack of beaches at headlands, where the energy of the waves is uch greater.